# print("Hello World!!! ")
# print('这是Python课程')
#
# if 5 > 2:
#     print("Five is greater than two!")
#
# if 5 > 2:
#     print("Five is greater than two!")
#     print("Five is greater than two!")

# x = 5
# y = "Hello, World!"
# print(x)
# x = "Steve" # x is now of type str
# print(x)
#
# x = "Bill"
# print(x)
# # is the same as
# x = 'Bill'
# print(x)
# aaaaaaaaa = 3
# print(y)

# # This is a comment.注释
# print("Hello, World!")
#
# print("Hello, World!")  # This is a comment
#
# # print("Hello, World!")
# print("Cheers, Mate!")

# x, y, z = "Orange", "Banana", "Cherry"
# print(x)
# print(y)
# print(z)
#
# x, y = y, x
# print(x)
# print(y)

# x = "awesome"
# print("Python is " + x)
#
# x = "Python is "
# y = "awesome"
# z =  x + y
# print(z)
#
# x = 5
# y = 10
# print(x + y)

# x = "awesome"
#
# def myfunc():
#     print("Python is " + x)
#
# myfunc()

# x = "awesome"
#
# def myfunc():
#     x = "fantastic"
#     print("Python is " + x)
#
# myfunc()
#
# print("Python is " + x)

# x = 10
# print(type(x))
# x = "Hello World"
# print(type(x))
# x = 29.5
# print(type(x))

# x = 27e4
# y = 15E2
# z = -49.8e100
#
# print(type(x))
# print(type(y))
# print(type(z))

# import random
#
# print(random.randrange(1,10))

# print("What's this?")
# print('What\'s this?')

# a = """Python is a widely used general-purpose, high level programming language.
# It was initially designed by Guido van Rossum in 1991
# and developed by Python Software Foundation.
# It was mainly developed for emphasis on code readability,
# and its syntax allows programmers to express concepts in fewer lines of code."""
#
# b = '''sss
# sss
# aaa
# bbb'''
# print(b)

# a = "Hello, World!"
# print(a[1])
# print(a[2:5])
# print(a[::-1])
# print(len(a))

# a = 2**100000
# c = str(a)
# b = len(c)
# b = len(str(2**100000))
# print(b)

# a = " Hello, World! "
# print(a.strip())
#
# a = "Hello, World!"
# print(a.lower())
# print(a.upper())

# a = "Hello, World!"
# print(a.split(","))

# txt = "China is a great country!!!"
# x = "ina" not in txt
# print(x)
#
# a = "Hello"
# b = "World"
# print(f'{a} {b}')
#
# age = 63
# txt = f"My name is Bill, and I am {age}."
# print(txt)

# print(8 > 7)
# print(8 == 7)
# print(8 < 7)

# print(5 / 3)
# print(5 % 3)
# print(5 // 3)
#
# print(5 & 3) # 001
# print(5 | 3) # 111
# print(5 ^ 3) # 110
# 5 = 101, 3 = 011
# 110 = 6
# print(5 >> 3) # 000
# print(5 << 3) # 101000
# a = 2
# print(a is None)

# thislist = ["apple", "banana", "cherry"]
# print(thislist[1])

# thislist = ["apple", "banana", "cherry", "orange", "kiwi", "melon", "mango"]
# print(thislist[2:5])

# thislist = ["apple", "banana", "banana", "cherry"]
# thislist.remove("banana")
# print(thislist)

# list1 = ["apple", "banana", "cherry"]
# list2 = list1.copy()
# print(list1, list2)
# list2[1] = 2
# print(list1, list2)
#
# a = 1
# b = a
# print(a, b)
# b = 2
# print(a, b)

# list1 = ["a", "b", "c"]
# list2 = [1, 2, 3]
# list3 = ["a", "b", "c"]
# list4 = [1, 2, 3]
#
# list1.extend(list2)
# print(list1)
# list3.append(list4)
# print(list3)

# thistuple = ("apple",)
# print(type(thistuple))
#
# #不是元组
# thistuple = tuple("apple")
# print(type(thistuple))

# thisset = {"apple", "cherry", "banana", "cherry"}
# thisset.add("orange")
# print(thisset)

set1 = {"a", "b" , "c"}
set2 = {1, 2, 3}

set3 = set1.union(set2)
print(set3)

x = {"apple", "banana", "cherry"}
y = {"google", "microsoft", "apple"}

z = x.difference(y)

print(z)